Shock absorber



M. FuNKHolYJsER SHOCK ABSQRBER Filed April 5, 1946 Mearior( Fumlyouser Y MQ@ @am ATTORNEYS Patented Jan. 4, 1949 SHOCK ABSORBER Mearick Funkhouser, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application April 3, 1946, `Serial No. 659,335

(Cl. 18S-88) claims. l

This invention relates to improvements in hydraulic shock absorbers particularly of the direct acting type.

It is among the objects of the present invention to provide a direct acting, hydraulic shock absorbed of simple and compact design capable of controlling both the approaching and separating movements of two relatively movable members, and in which one of said members is entirely devoid of any fluid ow control mechanism.

Compactness in the design of the shock absorber of the present invention is attained by utilizing the piston rod for the provision of the uid reservoir and by providing a piston on said rod which carries all of the iiuid ow control devices of the shock absorber.

Further objects and advantages of the present invention will be apparent from the following description reference being had to the accompanying drawings wherein a preferred embodiment ci the present invention is clearly shown.

In the drawings:

Fig. 1 is a longitudinal, sectional view of a shock absorber.

Fig. 2 is an enlarged fragmentary sectional View showing the construction of the shock absorber piston.

Referring to the drawings, the numeral designates the cylinder of the hydraulic shock absorber. A collar 2| is secured around said cylinder at its one end in any suitable manner such as welding or the like, this collar being exteriorly threaded to receive the threaded recess of a closure member 22. A gasket 23 is placed between the closure member and the end surface of the cylinder 20 to prevent fluid leaks at this end of the cylinder. The closure member 22 has an extending lug 24 provided with an opening 25, this lug forming a mounting member. By means of this, one end of the shock absorber may be attached to one of the relatively movable members whose movements the shock absorber is intended to control.

At the opposite end of the cylinder 20, bearing sleeve 2B fits within, this bearing sleeve being maintained in position by a collar 21 threadedly received by the cylinder 20. Bearing sleeve 26 slidably supports a tube which forms the piston rod 30. Said rod extends into the cylinder and is provided with exterior threads for threadedly engaging the piston 50. The other end of the piston rod 30 extends outside the cylinder 20 and has a flanged collar 3| secured about it in any suitable manner. Exterior threads on the collar 3| receive the threaded recess of a closure member 32, a seating gasket 33 being provided between said closure member and of the tubular piston rod 3|! to prevent iluid leaks at this point. Like closure member 22, this closure member 33 has a lug 34 extending therefrom provided with an opening 35. This lug forms a mounting member for this end of the shock absorber by means of which it may be attached to the other of the relatively movable members Whose movement the shock absorber is adapted to control. An opening 3&3 in the closure member 32 provides communication between the interior of the tubular piston rod 3B and atmosphere.

A collar i8 is secured about the cylinder 20 adjacent its upper end and to this collar 40 is attached one end of a collapsible and expandable fluid tight bellows 4| so that a leak-proof joint is provided between the end of the bellows and the collar 0 to Which it is attached. The other end of this bellows 4| is attached to the flange of collar 3| so as to provide a leak-proof connection therewith and so as to be movable with said flange as the piston rod 3D is reciprocated. Orices 42 in the tubular piston rod 30 adjacent the end thereof attached to the closure member 32 provide communication between the interior of the bellows 4| and the interior of the tubular piston rod 30.

The Fig. 2 in the drawings is an enlarged fragmentary sectional view illustrating in detail the construction of the piston 5U attached to the tubular piston rod 30. This piston slidably engages the inner wall of the cylinder 20. Its ends are each recessed and a plurality of fluid passages are provided in the piston for the transfer of iiuid from one side of the piston to the other. The recess at the one or upper end of the piston is interiorly threaded as at 5| for receiving the threaded end of the tubular piston rod 30. A valve cage 52 in the form of a cylinder having an inwardly extending flange 53 at its outer end and an outwardly extending flange 54 at its inner end ts within a counterbored portion at the end of the tubular piston rod 30, the outwardly extending flange 54 being clamped between the bottom surface of the recess in piston 5D and the end of the tubular piston rod 30 and thereby is rigidly held in position. This valvecage 52 forms what may be termed a fluid receiving chamber 52a in the piston. The inwardly extending iiange 53 of the cage 52 is annular in shape and thus provides a central opening or port 55 which provides communication between the fluid receiving chamber and the interior of the tube 30 and is surrounded by an annular ridge 56 extending downwardly toward the bottom of the valve cage and forms an annular valve seat against which the fluid intake valve 51 is urged by a spring 58 interposed between said valve 51 and the bottom of the recess in piston 5D. This valve 51 has a tubular body portion 59 surrounded by a perforated washer 69 which holds the valve central of the cage and thereby assures engagement of the valve with the annular seat 56. The cylindrical body portion 59 of valve 51 slidably supports the tubular stem portion of valve 62, the one end of which has an enlarged head portion 63 normally engaging the valve 51 due to the provision of a spring 64, which is interposed be tween the washer 60 and another washer 65 secured to the outer end of the valve 62. An orifice 66 in the one side of the stem portion of the valve 62 provides communication between the interior of the said valve and an annular groove 61 formed in the under surface of the head 63 adjacent valve 51. This annular groove 61 communicates with a space 68 beneath a cover plate 69 secured to the outer end of the valve in any suitable manner. The spring 58 is of much lighter construction than the spring 64 and thus valve 51 is urged against its seat 56 with substantially less pressure than the valve 62 or more particularly its head portion 63 against the valve 61 by the spring 64. Therefore a lesser fluid pressure will move valve 51 from engagement with its seat than is necessary to move valve head 63 from engagement with valve 61 to establish a fluid ow through the valve 62.

A channel in the side of the piston for a portion of its length communicates with a duct 1| which leads into the fluid receiving chamber 52a formed by the valve cage 52. Channel 10 terminates in the lower end of the piston 50 and opens into the lower working chamber 12 of the cylinder.

Another channel 13 in the side wall -of the piston 59, extending from its top end, longitudinally for a portion of the pisto-n length, connects with a passage 14 which communicates with the recess 16 in the lower end of the piston. Thus channel 13 and passage 14 -co-nnect the upper working chamber 15, an annular space between the inner and outer walls of the cylinder 20 and piston rod 30, with said lower recess 16. A counterbored portion of recess 16 is interiorly threaded as at 11 for receiving a plug 18.

A series of passages 89, arranged in a circular row in the piston 50, provide communication between iluid receiving chamber 52a and the recess 16. Two spaced concentric, annular ridges 8| and 82 extend from the end wall of recess 16. The passages 80 terminate in the space between these two ridges 8| and 82 which form annular seats for the valve 83. A stud 84 is centrally threaded in the piston portion between the two recesses in the piston, said stud having an enlarged head portion against which one end of spring 85 abuts, the other end of the spring engaging valve 83 yieldably to urge it upon the seats or ridges 8| and 82 the-reby closing passages 80 from communication with recess 16.

The outer end of plug 18 extending from the piston into the lower cylinder chamber 12 has an annular ridge 99 extending therefrom. A plurality of passages 9| in plug 18 terminate in the outer end of the plug within the confines of the annular ridge 90'and communicate with there cess 16 in which valve 83 is situated. A threaded central opening in the plug 18 receives the threaded shank of a stud 93 which has an enlarged head 94. A resilient disc valve 95 in the form of a ring, ts about the shank of vstud 93 and is tightly clamped thereby against the end surface of plug 18 so that said valve normally engages the annular ridge 99 and thereby closes passages 9| from communication with the lower cylinder chamber 12. An abutment collar 96 with a tubular body portion slidably tting upon stud93 and an. outwardly extending, annular ange engaging the disc valve 95 is engaged by lone end of a spring 91 the other end of said spring seating on the stud head 94. This spring 91 acting through collar 96 urges valve 95 upon its seat, the annular ridge 90, at a predetermined pressure.

As has been stated.'the present shock absorber is adapted to control both the approaching and separating movements of two relatively movable members as, for instance, the frame and axle of a vehicle. The member 34, to which the piston rod 39 and its piston 59 is attached, may be anchored to the frame of the vehicle while member 24, to which the cylinder 20 is attached, may be anchored to the vehicle axle.

When the two relatively movable members 24 and 34 are moved toward. each other the piston rod 30 and its piston 58 are thrust int-o the cylinder 26, the piston thereby exerting a pressure upon the fluid in the lower chamber 12. As a result fluid will be found through the piston channel 18, duct 1| and into the chamber dened by the valve cage 53 which is closed by the mechanism including valves 51 and 62. The passages leading from this chamber are normally closed by valve 83. Valves 62Vand 83 are the only ones operativev to establish a uid ow from within the val-ve cage 53 and inasmuch as the spring urging valve 83 closed is weaker than spring 64 urging valve 62 closed, valve 83 will be the first to yield to-.iluid pressure and establish a fluid flow in response yto uid pressure in the said valve cage chamber. With valve 83 01T its seat uid may now flow through passages 80 into the chamber of recess 16 thence through duct 14 channel 13 into the upper cylinder chamber 15. Chamber 15 is an annular chamber between piston rod 30 and the cylinder 20 and therefore is of smaller cubical content than the lower cylinder chamber-12. Therefore all of the uid displaced by the piston from the larger chamber 12 cannot be received by the upper, smaller cylinder chamber 15. That portion of the fluid displaced by the piston rod in the upper cylinder causes valve 62 to be moved against the eifect of spring 64 and thus the fluid displaced from .chamber 12 and not received by chamber 15 flo-ws through valve 62, its side orifice 66 and past the annular edge of head 63 which is now lifted from engagement with valve 6,2. From valve 62 the fluid flo-w continues through the opening 55 in -the valve cage intothe interior of the piston rod 3l) which is hollow to provide a fluid reservoir |06.

To actuate valve 62 against the eifect of its spring 64 so that the head 63 is lifted from engagement with its seat on the now stationary valve 51, a predetermined fluid pressure must ex` ist in the valve cage 53. When this is effected, the restriction to uid flow established by the annular space between. vthe head 63 andvalve 51, will cause the shock absorber to resist the approaching movements of the two relatively movable members between which it is mounted.

When members 34 and 24 are moved apart due to the separating movement Vof the two relatively movable members between which they may be connected, the piston rod and its piston S is moved from the closed end of the cylinder toward the sleeve bearing .26 which forms the head of the upper working chamber 'i5 of the cylinder. Now the piston 5d eXerts a pressure upon the fluid in the annular cylinder chamber l5; and in response thereto fluid is forced through the piston channel i3, passage M into the space in recess 76 between plug 18 and valve 83. The fluid pressure through passages 9i in plug 18 upon valve S5 will, when attaining a predetermined value, move said valve S5 from its seat 9@ against the effect of spring 9'! thereby establishing a restricted fluid flow from the upper to the lower cylinder chamber.

Fluid from the smaller, upper cylinder chamber will not completely satisfy the fluid demand of the lower chamber as the piston moves toward the sleeve bearing 26 and thereby creates a subatmospheric pressure in said lower chamber. Thus iluid in the interior of the piston rod or more particularly the fluid reservoir will urge valve 57 from its annular seat 55 against which it is normally urged by the comparatively light spring 58. Now fluid may flow substantially freely from the reservoir l' through opening 555 in the valve cage 53, past valve 5l and then through the valve cage, passage ll, groove 'l0 in the piston into the lower cylinder chamber, thereby compensating for the insuiiicient amount of iluid receivable from the smaller upper cylinder chamber l5.

rlhe fluid in the reservoir i 0B within the piston rod 3i] is at atmospheric pressure inasmuch as duct 3G in member 32 connects the reservoir with atmosphere at all times. Fluid in the reservoir may also rise to openings 42 in which case it will spill over into the bellows element il which is tightly secured to both the cylinder and pistonrod, in the lattel` instance by the collar 3|.

From the aforegoing it may be seen that applicant has provided a sturdy and compact single acting shock absorber in which one element serves both as a piston rod and a fluid reservoir and in which the piston carries all valves necessary to control iluid now so that the shock absorber provides the desired resistance to control both the separating and approaching movements of the two relatively movable members to which said shock; absorber is attached.

While the embodiments of the present invention as herein disclosed, constitutes a preferred forni, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

l. An hydraulic shock absorber comprising a uid containing cylinder having a closed and an open end and a bearing bushing in its open end; a piston in the cylinder having uid passages and forming upper and lower working chambers in the cylinder; a tube slidably supported in the bearing bushing and having its one end attached to the piston; a valve cage in the tube and held between the tube and piston said valve-cage providing a iluid receiving chamber in the piston and having an annular Valve-seat extending into the fluid receiving chamber; a valve yieldably urged against the annular valve-seat and movable to establish a fluid flow from the tube through the fluid receiving chamber and into the lower Working chamber; said valve having a tubular extension; a valve slidably supported in the tubular extension of the irst mentioned valve and movable relatively thereto to establish a fluid flow from the lower working chamber through the fluid receiving chamber and into the tube; a valve yieldably urged against the piston and movable relative thereto to open certain piston passages for establishing a iuid ilow from the lower working chamber through the iiuid receiving chamber into the upper working chamber; and another valve normally urged to close certain fluid passages in the piston and operable by fluid pressure from the upper working chamber to establish a now into the lower working chamber.

2. An hydraulic shock absorber comprising a closed, iiuid filled cylinder; a recessed piston in said cylinder; a valve-cage in said piston forming a fluid receiving chamber therein; a hollow piston rod extending through one end of the cylinder and into the recess of the piston to secure the valve cage therein the interior of the rod being in communication with the fluid receiving chamber and with fluid ow passages in the piston; and a plurality of fluid flow control devices in the piston, two of which are rendered eiective to establish fluid flows in response to movement of the piston in one direction, the one of these two establishing a substantially unrestricted flow from the pressure side of the piston, through the iuid receiving chamber to the opposite side of the piston, the other a restricted flow from said pressure side of the piston through the fluid receiving chamber and into the hollow piston rod, two other of said plurality oi fluid flow control devices being rendered eective to establish fluid flow in response to operation of the piston in the opposite direction, the first of these two other devices establishing a substantially unrestricted duid :dow from the hollow tube through the fluid receiving chamber into the cylinder chamber at the opposite side of the piston and the second of these two other devices establishing a restricted iiuid flow from the cylinder chamber around the piston rod to the cylinder chamber on the 0ppcsite side of the piston and independently of the fluid receiving chamber.

3. An hydraulic shock absorber comprising, a cylinder closed at one end and having a bearing sleeve secured therein at its other end, said cylinder being filled with a fluid; a tube slidably supported by the bearing sleeve and extending into the cylinder; a piston in the cylinder secured to the inner end of the tube said piston having duid passages; a closure member secured to the outer end of the tube; a collapsible and extendible liquid tight sleeve having one end sealingly secured to and about the cylinder and its other end to the closure member of the tube, the inside of said sleeve being in communication with the interior of the tube by openings in the tube more adjacent its outer end; a duct in the closure member of the tube connecting the eXtreme outer end of the tube interior with atmosphere; valves in the piston controlling the ow of fluid between the cylinder chamber on each side of the piston and between said chambers and the interior of the tube in response to reciprocation of the piston in said cylinder; and mounting blocks provided by the closure members of both the cylinder and tube.

4. A hydraulic shock absorber comprising a iiuid containing cylinder closed at one end and having a bearing sleeve at its other end; a tube slidably extending through said bearing sleeve into the cylinder; a piston in the cylinder, attached to the tube and forming cylinder working chambers on each side of the piston, said piston having a fluid receiving chamber with three separate ports, one port communicating with the tube, the other two each with a working chamber respectively; and valve mechanisms normally closing the ports communicating with the tube and with the one cylinder chamber, the port communicating with the other cylinder chamber being constantly open, the valve mechanism controlling the port to said one cylinder chamber being operative to open its port in response to a lower fluid pressure than the valve controlling the port to the tube as the piston is moved toward the closed end of the cylinder.

5. A hydraulic shock absorber comprising a fluid containing cylinder closed at one end and having a bearing sleeve at its other end; a tube slidably extending through said bearing sleeve into the cylinder; a piston in the cylinder, attached to the tube and forming cylinder Working chambers on each side of the piston, said piston having a iluid receiving chamber with three separate ports, one port communicating with the tube, the other two each with a working chamber respectively; a valve normally closing the port between the receiving chamber and tube; another valvey normally closing the port between said chamber and the cylinder working chamber through which saidv tube extends, said other valve being operative to open its port in response to a lower uid pressure in the receiving chamber than said first mentioned valve.

6. A hydraulic shock absorber comprising a iluid containing cylinder closed at one end and having a bearing sleeve at its other end; a tube slidably extending through said bearing sleeve into the cylinder; a piston in the cylinder, attached to the tube and forming cylinder working chambers on each side of the piston, said piston having a uid receiving chamber with three separate ports, one port communicating with the tube, the other two each with a Working chamber respectively; a compound valve mechanism normally closing the port between the receiving chamber and tube, said valve mechanism being operative to establish a substantially free flow of uid from the tube into said chamber as the piston moves in one direction and a restricted ilow of fluid from the said receiving chamber into the tube as the piston moves in the opposite direction; and a valve normally closing the port leading from said receiving chamber to the cylinder chamber vthrough which the tube eX- tends, said valve being operative ata lower fluid pressure in the receiving chamber than the uid 110W restricting valve of the compound valve mechanism.

'7. A shock absorber in accordance with claim 4, in which, however, the piston is provided with a valved uid passage, independent of the fluid receiving chamber, and operative in response tov movement of the piston away from the closed end of the cylinder, to establish a fluid ow from the cylinder working chamber through Which the' tube extends, into the other cylinder working chamber.

8. A shock absorber in accordance with claim 4,

in which, however, the piston is provided with a valved fluid passage, independent of the uid receiving chamber but including a portion of the port connecting said chamber with the cylinder chamber through which the tube extends,'said valved fluid passage being operative to establish a fluid flow from the cylinder chamber containing' the cylinder for directing iluid to theicylindery chamber adiacentthe closed end of the cylinder, the said valved passage establishing a ow fromV the tube containing cylinder chamber, the compound valve mechanism from the tube.

l0. A hydraulic shock absorber comprising` a fluid containing cylinder closed at one end and having a bearing sleeve at its other end; a tube slidably extending through said sleeve into the cylinder; a piston in the cylinder dividing it into two working chambers, said piston having a recess in its one end for receiving thek one end of the tube to which it is' attached; a cage in the tube, cooperating with the piston to form a iluid receiving chamber therein, said chamber having a plurality of separate ports, one communicating with the tube, the other two leach communicating with a Working chamber respectively; and valve mechanisms normally closing the ports communicating with the tube and with the one cylinder chamber, the port communicating with the other cylinder chamber being constantly open, the valve mechanism controllingV the port' to said one cylinder chamber beingy operative to open its port in response to a lower fluid pressure than the valve controlling the port The following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date Becker Dec. 12, 1939 Number 

